I built a cannon a few years ago. The chamber is 4" sch40 PVC from McMaster. It's been sitting in my garage at my apartment for the last 2 years. Should I be worried about the PVC becoming brittle? It's been exposed to temps over 100* and below 0* in the garage (Indiana weather). No direct sunlight.

What tech said. Besides, you house probably has PVC water lines in it that are much older than the cannon. A PWS may occasionally hit 100 PSI (or much higher in water hammer situations) but you don't hear about decades old PVC failing.

Dippert, its plastic. Does plastic break up over time? Not that anyone has heard of. I think your fine. But if you want to test it, bury it, then fire it. If its pneumatic, put pressure in until you hit the pressure you want, then done. Leave it for a few hours, and then come back. If it has not blown up, its safe to use.

Well,PVC does not readily degrade when exposed to sunlight (ultraviolet radiation) due to natural UV inhibitors present in the material. Short-term exposure to sunlight, such as during construction, is typically not a problem for PVC pipe. PVC piping may be used in outodoor applications when the piping system is painted with a light-colored water based acrylic or latex paint(Do not use oil based paints) that is chemically compatible with PVC. When painted, the effects of UV exposure are significantly reduced.

Doctore wrote:Well,PVC does not readily degrade when exposed to sunlight (ultraviolet radiation) due to natural UV inhibitors present in the material. Short-term exposure to sunlight, such as during construction, is typically not a problem for PVC pipe. PVC piping may be used in outodoor applications when the piping system is painted with a light-colored water based acrylic or latex paint(Do not use oil based paints) that is chemically compatible with PVC. When painted, the effects of UV exposure are significantly reduced.

Depends on what "readily" means and whether of not the particular PVC actually has the UV inhibitors . Several years in the sun, unpainted, and the PVC will be severely pitted. Even PVC used for exterior trims will pit in full sun within a few years if unpainted.